Bad Moon Rising
by Paige Elise Hale
Summary: We've all seen "Scott's twin sister" stories, but this one is different. In this one, Isaac has a twin sister named Isabella. She meets Derek right off the bat and starts to fall for him. She's totally supportive of Isaac's choice to become a werewolf. But when she's caught in the crossfire with Matt and the Kanima, will Derek let her go or turn her? And how will Isaac take this?
1. Derek and Isabella

Bad moon rising

**I do not own Teen Wolf in any way.**

**A/N-You guys wanted a Derek/OC. Well here it is. I am not trying to make Isabella into another Alison. I promise you this. Her talent with a bow and arrow will change later on in the story.**

**I see the bad moon arising **

**I see trouble on the way**

**Bad Moon Rising Cover by Mourning Ritual**

* * *

The Lahey twins seemed to always be in sync with each other. They both got up at the same time and got ready at the same time.

When they rode their bikes to school, their movements were in sync.

They never left each other's side.

That was about to change.

* * *

Isabella Lahey was the eyes and ears of Beacon Hills High School.

If you wanted to know something about someone, you went to Isabella.

This unfortunately was how she figured out about werewolves.

Earlier in the year, one of the buses had been damaged and it had been covered in blood.

She sat near Scott and Stiles that day.

"Maybe you caught a rabbit or something", Stiles had said.

"And did what?" Scott asked.

"Ate it", Stiles said.

"Raw?" Scott asked, his voice cracking.

"No, you stopped to bake it in a little werewolf oven", Stiles said sarcastically.

It explained the howls she had heard in the woods at night.

She kept this little secret to herself, until one day, she decided to see for herself.

* * *

"I'm heading out", Isabella said kissing her twin on the cheek.

She grabbed her bow and arrows and grabbed her bike.

Isaac never asked where she went or what she did when she left with her bow, but he knew she was safe.

* * *

Isabella pulled up to the Beacon Hills Preserve. She dropped her bike and pulled out her bow. She knocked an arrow and went inside into the woods. She normally would use the trees for target practice, but something felt off today. She quietly walked through the woods. She heard a twig snap. She drew back on her bow string, ready to shoot. She was suddenly forced up against a tree and her bow was knocked from her hands.

In front of her stood an animal like man.

He had bright red eyes, pointed ears, and black hair/sideburns.

It slowly shifted into a man with pale green eyes and strong jaw line.

He stepped back from her.

She was taken aback by how beautiful he was.

"It's dangerous to be out here alone", he told her.

"Who are you?" she asked him, picking up her bow.

"Are you a hunter?" he asked.

"No. You can't answer my questions with a question", she told him.

"My name is Derek Hale", he said.

"You're a werewolf! I know what you are", she said.

"You're not scared? Why? How?" he asked her.

"It's interesting to me" she asked, "I'm Isabella Lahey. I know because I heard Scott McCall and Stiles Stilinski discussing it in class".

Derek actually growled. "I'm going to kill those two. Wait…Lahey? Isaac's sister?" Derek asked.

"Twin sister actually", she said holding out her hand.

Derek looked at it.

"You shake it", she told him.

"I know what to do", he said, "What I'm wondering is why I have to shake it".

"It's to show that we're on the same side. I can provide you protection", she said.

He stepped forward and placed his hands on either side of her head, caging her in. "What makes you think I need protection?" Derek asked her.

"Well you asked me if I was a hunter, which means hunters must be after you. Think of me as your own personal hunter", she said.

"You're a girl", he said.

"Well spotted", she quipped.

This girl was just as sarcastic as Stiles was and it was starting to annoy him.

"You're very annoying, do you know that?" he snapped.

"I've been told it's one of my best qualities", she said.

He growled at her.

Isabella stood stone-faced. "You don't scare me Derek. The only man who can scare me is my father", she told him.

"Does he…?" Derek asked.

"No. He doesn't touch me. He only beats Isaac. I try to stop it, but he ends up locking me in my room", she said. Her phone beeped. "I've got to go Derek", she told him, "One more question. Are you going to bite my brother?"

Derek's silence gave her her answer.

He stepped back and she grabbed her stuff.

She leaned up and kissed Derek on the cheek. "I have a feeling we'll be seeing each other soon", she said.

* * *

**What do you guys think?**


	2. Why do you want the bite?

Chapter 2

**I do not own Teen Wolf in any way.**

**A/N-Because of all the follows, favs, and reviews, I'm giving you a second chapter today.**

* * *

"So explain to me why I'm here again", Isabella said.

"You're my leverage", he told her.

"I trust my twin", she said, "Not my fault if you don't".

The two watched the police question her brother.

Derek used his werewolf hearing to listen in.

"It's Lahey. Isaac Lahey", Isaac told the sheriff.

"You work for your father, Isaac?" the sheriff asked.

"When he's not in school. Which is where he needs to be in 20 minutes", his father said.

"Yeah, I understand that. But I've got a missing teenage girl, and our k - 9 unit led us here. She's not wearing any clothes, and if she's out here tonight, and the temperature really drops…" the sheriff said.

"I'm sorry, I - I didn't see anything", Isaac told him.

"Trust me, if he saw a naked girl outside a computer screen, he'd remember", their father joked.

The sheriff gave him an unsure look and said, "How'd you get that black eye, Isaac?"

"School", he said.

"School fight?" the sheriff asked.

"Nah, lacrosse", Isaac lied.

"Lacrosse? You play for beacon hills?" the sheriff asked.

"Yeah", Isaac answered.

"My son plays for the team. Well, I mean, he - he's on the team. He doesn't typically play. Not yet, anyway", the sheriff explained.

Isaac glanced over across the graveyard and was shocked to see his twin standing beside Derek Hale.

Bow and arrows slung across her back.

He watched as she raised her finger to her lips and winked.

"It's, uh - Something wrong, Isaac?" the sheriff asked.

"No. Oh, no, sorry. I was just remembering, I actually have a morning practice to get to", Isaac lied.

"Just one more question. You guys get many grave robberies here?" the sheriff asked.

"A few. Usually, they just take stuff like jewelry", Isaac told him.

"What'd this one take?" the sheriff asked.

"Her liver", Isaac said.

When he glanced back, both Isabella and Derek were gone.

* * *

"I've got to get to school. I'll come by later to get my bow", Isabella told Derek.

He grabbed her phone.

"What the hell?" she asked.

"You have no idea where I live. I'll come get you this afternoon", he told her. He handed back her phone and she noticed that he had put his number in her phone.

She grabbed her bike and sped off for school. She managed to dodge Isaac until he grabbed her arm and dragged her into an empty classroom.

"Why were you with Derek Hale this morning?" Isaac asked.

"What's the matter big bro? Afraid I can't handle myself against the big bad wolf?" she asked him.

"You know?" he asked.

"Yeah, dumb and dumber a.k.a. Stiles and Scott can't keep their voices down in class", she told him, "Why do you want the bite anyway?"

Isaac sighed and said, "I'm tired of getting pushed around. Our father beats me every chance he gets. One of these days, he's going to get bored with me and move onto you".

"Isaac, you don't have to do this for me", she told him.

"Yes I do", Isaac said, "You don't understand".

"Then make me", she said.

"I want to feel powerful for once in my life. I want to be able to protect you", he said, "I can do a hell of a lot better than Derek".

"Why are you so worried about Derek? If you're going to be his beta, you're going to have to get over the fact that Derek somewhat likes me", she said.

"Wait…you want me to get the bite?" he asked her.

"Not really, but if this is what you want, I'm powerless to stop you", she said, "You're my twin. My other half. If this will make you happy, then go ahead and do it".

Isaac hugged his twin sister as the bell rang.

"Off you go. Father will kill you if you miss a class", she said pushing him out the door.

* * *

During her free period, Isabella walked through the school. She was suddenly pulled into a closet.

A hand clamped down on her mouth.

"Don't scream", Derek's deep voice said in her ear. He let go and she slapped him.

"Thank you for scaring me, jerk", she said holding her chest.

He shocked her by grabbing her head and kissing her. When he pulled away, she was breathless. "I should have done that this morning", he told her.

"Yeah, you should've", she said panting.

The bell rang.

She stole one last kiss and left the closet.

Yep, she was falling for Derek Hale.

Her brother's soon-to-be Alpha.

* * *

**I've also noticed that this story has been added to a community. I don't know which one of you did it, but thank you so much! I've never had any of my stories added to a community! I love you guys so much! Derek kisses for everyone!**


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